Automatic plumb bob



Nov. s, 1938. E, s BUSH 2,136,072

AUTOMATIC PLUMB BOB Filed July l5, 1956 mmky A Traer/EV Patented Nov. 8,1938 PATENT OFFICE AUTOMATIC PLUMBI BOB Eugene S. Bush, St. Louis, Mo.,assigner to Bush- Harman Products, Inc., St. Louis, Mo., a corporationof Missouri Application July 13, 1936, Serial No. 90,376

1 Claim.

This invention relates generally to plumb blobs, and more specificallyto a plumb bob the supporting cord of which is connected to the weightin such manner that when not in use the cord will be automatically woundup within the bob,

and wherein any length of cord may be withdrawn from the bob and the bobclamped to the cord to restrain the operation of the cord-winding meansuntil it is desired to release same, the

'10 predominant object of the invention being to provide an extremelysimple device of this type,

which is an improvement on the automatic plumb bob covered by UnitedStates Letters Patent 1,357,270, granted to me on November 2, 1920. Fig.1 is a view of the improved plumb bob illustrating same partly inelevation and partly in vertical section.

Fig. 2 is an enlarged vertical section on line 2 2 of Fig. 1.

Fig. 3 is a section on line 3-3 of Fig. 2.

Fig. 4 is a section on line 4-4 of Fig. 2.

Fig. 5 is a section on line 5--5y of Fig. 2.

Fig. 6 is a fragmentary detail showing the manner in which an end of thecord is attached to the reel of the plumb bob.

Fig. 7 is a perspective of a part of the cordwinding mechanism of theimproved plumb bob.

In the drawing, wherein is shown for the purpose of illustration,merely, one embodiment of the invention, A designates the improved plumbbob generally, said plumb bob including a bob of weight I and asupporting cord 2. I'he bob I is of the usual `shape and comprises alower section 3 and an upper section or cap 4, said upper sectionpreferably being detachably connected to the lower section bycooperating screwthreaded portions 3 and 4' formed on said lower andupper sections. At its upper end the lower section 3 is provided with achamber 5 formed therein, and the upper section 4 ispro-vided with achamber 6 which, when the upper section or cap 4 is in place on thelower section 3, cooperates with the chamber 5 to provide a singlechamber. The upper portion 4 of the bob I is provided with an upwardlyextended portion I through which an opening 8 is formed longitudinallythereof, said opening being of enlarged diameter at its upper end asindicated at 8', and this enlarged portion being screw-threaded as seenin Figs. 1 and 2. The supporting cord 2 of the plumb bob is extendedthrough the opening 8-8, and 9 designates a clamping element which islocated Within the portion 8 of said opening. The clamping element 9 isformed of spring metal and comprises anV expansible split ring I0 withwhich a pair of oppositely disposed, upwardly extended arms II areassociated. The arms Il at their upper ends are provided withsubstantially parallel portions, and the lower portions of said arms areinclined as shown in Fig. 1, said arms being formed integral with thesplit ring I0 at its upper edge. I2 designates a screw-threaded plugwhich is screwed into the screw-threaded portion 8 of the opening 8, thelower edge of said plug being adapted to contact with the inclinedportions of the arms II when the plug I2 has been screwed inwardly intothe portion 8 of the opening 8 a sufficient distance.

The supporting cord 2 passes between the upper, parallel end portions ofthe arms Il, and when it is desired to clamp said supporting cord so asto prevent movement thereof with respect to the bob I, the plug I2 isscrewed downwardly into the opening 8. This will draw the upper ends ofthe arms II toward each other in a manner to tightly grip the supportingcord, whereby movement of said supporting cord relative to the bob isprevented. The arms Il are possessed of sufficient resiliency to causesaid arms to move away from each other when the lower portion of theplug I2 is moved upwardly, thus permitting free movement of thesupporting cord between said arms.

At the upper wall of the chamber 5 within the upper section or cap 4 isa screw-threaded projection I3 through which the opening 8 passes, andI4 designates an inverted U-shaped frame which isprovided with ascrew-threaded opening I 4 in its upper wall, which receives thescrewthreaded extension referred to so as to support the U-shaped framein the chambers 5-6 within the bob I. The U-shaped frame I4 ispossess-ed of sufcient spring or resiliency so that the downwardlyextended legs of said frame may be moved outwardly from their normalpositions, as illustrated in Fig. 2, and these downwardly extended legssupport the cord-winding mechanism C of my improved plumb bob.

The cord-winding mechanism C of the improved plumb bob includes a reelI5, which is in the form of an element having an annular wall I6 and arear Wall I1, said annular Wall being provided with annular outstandingiianges I8 between which the supporting cord is wound on the outer faceof the annular wall. The reel I5, when considered apart from themechanism associated therewith, is open at the side opposite to the sidethereof at which the wall I 1 is situated, and said reel is providedwith a centrally located extension 20 which is formed integral with thewall I'I and extends therefrom toward the opposite, open side of thereel. The extension 2S terminates short of the outer face of the reel atthe side thereof opposite to the side at whichthe wall I'I is located,as shown in Fig. 2, and this extension is provided with an elongatedopening 2I formed longitudinally thereof in which the inner portion of ashort shaft 22 is disposed. The short shaft 22 has gear teeth formedthereon providing a pinion 23, portions of the shaft 22 being formed atopposite sides of said pinion, and the inner portion of said shaft isdriven into the opening 2l to provide a drive t, whereby said shaftmoves with the reel I5.

Located within the reel l5 is a spring barrel 24 which comprises anouter annular wall 25 arranged in contact with the inner face of theannular wall I6 of the reel I5, and a rear wall 26 arranged in contactwith the inner face of the end wall Il of said reel. The spring barrelincludes alsdan integral sleeve portion 2l which is located centrally ofthe spring barrel and extends inwardly from the wallY 26 thereof. sleeveportion`2'l is arranged to embrace the extension 23 of the reel as shownclearly in Fig. 2,

vsaid sleeve portion 21 and said extension 26 terminating in coincidencewith each other.

28 designates a spring arbor which is in the fform of a cylinder whichembraces the sleeve portionZI and extension 29 of the spring barrel andreel, respectively. At its outer end the cylindrical spring arbor`28 ispartially closed, as

indicated at 2S' inFigs. 1 and 7, and said outer end of the arbor ispartially cut away as indicated at 29 in Fig. '7, so as to `provide thearbor with an outer end which is substantiallyY semicircular in shapeand of reduced diameter in one direction. The flat top faceLB of theouter end portion of the arbor28 is provided by cutting the outer endportion of the arbor .parallel with its l axis, and this at face 3) isjoined by a flat face 3| which is extended at a substantial right angleto theiface 3l). The opening in the arbor which results from cuttingsame as indicated exposes the interior of the arbor, and the upperportion of the .pinion 23 already referred to herein is presented'atsaid opening. The outer portion of the short shaft 22 is journaled in anaperture formed in the outer end of the spring arbor 28, and @saidsubstantially semicircular end portion ofthe arbor is extended into acorrespondingly shaped aperture in the adjacent leg of the frame I4,whereby said arbor is prevented from rotating.

Arranged within the spring barrel of the cordwinding mechanismimmediately adjacent. to the outer, .open end thereof is aniinternalgear` 32 (Figs. 2 and 3); said internal gear being fixed to androtatable with the spring barrel 24. IThe outer end of the spring barrelisclosed by a plate 33 which rotatably supports an intermediate pinion34. The intermediate pinion 34 meshes with the internal gear 32 and withthe pinion 23, whereby motion is transmitted from vone of the gears32-23 to the other thereof. VThe plate 33 is of varying thicknesses,said plate being relatively thin at its upper portion where theintermediate gear 34 is located and being thicker at its lower portion,the thickness of said plate at v its lower portion being approximatelythe same as the combined thicknesses of the upper plate portion andtheintermediate gear. The plate 33 is of the approximate diameter oftheinterior of the reel I5, asshown in Fig. 2, and this plate is providedwith an aperture 35 of theshape -and tion of the spring 36.

The

. 31 (Fig. 4) which is carried by said spring barrel and extends throughan aperture in the end por- The opposite end of the helical spring 36 isfastened to the spring arbor 28 and engages said spring arbor in themanner shown-clearly in Fig. 4. The helical spring is shaped to providean inner circle 40. A rivet or other fastening device 42 is extendedthrough a portion of the spring comprising the inner circle and into anopening 42 in the spring arbor 28, whereby said spring portions are heldin their proper positions. When the spring is being wound up, as whenthe supporting cord is pulled out the tendency is for the end portion ofthe spring to'move in the direction suggested by the arrow in Fig. 4.

' In the Ause of my improved plumb bob, out- .'ward movement of thesupporting cord results,

through the operation of the cooperating gears,

Vin the springbarrel being rotated in the oppo-.g Vsite direction to thedirection of rotation of the reel, whereby the helical spring is woundup, and when the cord is released the spring will rotate the reel torewind Vsaid cord. If it should be desired to clamp the cordv to preventmovementg35 thereof with respect tothe bob, this may be accomplished byscrewing the plug I2'downwardly,

- as alreadyexplained, to draw the clamping arms II together to thecord-clamping position.

An important feature of the' invention resides; in the fact that theentire cord-winding mechanism of my improved plumb bob is in the form ofaunitwhich is conveniently detachable from the bob, it being necessaryto merely unscrew the upper section or cap 4 fromthe lower section ofvthe bob, whereuponthe cord-winding mechanism may be unscrewed from thescrew-threaded extension'l3 `of said upper section or cap. The

Vcord-winding unit may then be taken apart by springing the'legs ofthe'U-shaped frame apart to free thespringarbor 28 from the aperturesin-said legs in which it is normally disposed. The various parts of thecord-winding mechanism may thenY be lifted out of place, as no fas--tening devices are employed to secure said parts together. To removethe helical spring it is only -necessary to disengage the outer end ofsaid Y spring from the `pin V37, when said spring may be lifted out.When the cord-winding mechanism-is assembled, as shownV in Fig. 2, thelower ends vof the legs of the U-shaped frame VI4 contact with thecurvedbottom wall of the chamvber 5,' whereby said legs are preventedfrom spreading.

Thecord 2'is attached at its inner-end to the mreel in the mannerillustrated in Fig. 6; that is to say, one ofthe annular flanges I8 isprovided with a pair-of slots I8' through which the cord .is passedinthe manner illustrated. By so at- Ltaching thecord to the reel theknot 2 is located Vvat the inside of the reel, where it will not inter--ferewithfree rotation of the reel.

' I claim: Y In a spring windngireel, a hollow winding element, ancoilspringA and .spring case therein, a.'

hollow spring arbor secured to the inner end secured to the hollowWinding element, and a of the spring, the outer end of the spring beinggear train operable by said winding pinion reconnected to the case, arotatable member exsponsive to rotation of the Winding element fortending internally of the arbor, a winding pinrotation of the springcase.

ion carried by said rotatable member, said member and pinion beingco-axial with and rotatively EUGENE S. BUSH.

